The faint whispers of a genetic conspiracy coursed through the corridors of Shanghai No. 6 Hospital on the evening of Sept. 12, 1980. It was shortly after 7 p.m., and a patient in the maternity ward had just endured an excruciating labor to give birth to a baby boy. An abnormally large baby boy. The doctors and nurses on duty should have anticipated something out of the ordinary. The boy's parents, after all, were retired basketball stars whose marriage the year before had made them the tallest couple in China. The mother, Fang Fengdi, an austere beauty with a pinched smile,...